According to German Published Patent Application No. 27 55 400, an electromagnetic fuel injector which can be used in fuel injection systems of internal combustion engines is known. This fuel injector is characterized by relatively short injection times. The fuel injector is designed in such a way that the entire pressure drop basically occurs through injection holes located downstream of a valve seat which interact with a sphere-shaped valve closing element. The valve closing element is located in a dead area between the valve seat and the injection holes opening in the direction of the fuel flow. When the valve is closed, the valve closing element is pressed against the valve seat with the help of a plunger. The plunger has the same diameter as the valve seat, and system pressure of the fuel is constantly applied to it in the direction of the closing movement. The fuel is supplied through a channel in the valve housing, away from the plunger, to the valve closing element from below which can thus complete the opening movement by lifting from the valve seat.
According to German Published Patent Application No. 38 43 862, an electromagnetically actuatable valve as a fuel injection valve, which is embodied as an inward-opening injection valve, is known heretofore. The valve is actuated by an energizable electromagnet, a sphere-shaped valve closing element interacting with a rigid valve seat in order to open and close the valve. If current is supplied to the magnet coil of the electromagnet, a starting movement is produced via an armature that is attached to an axially movable valve needle, this raising the valve closing element—which also belongs to the valve needle—off the valve seat so that the valve is opened. Herein, the connecting element of the valve needle, which is arranged between the armature and the valve closing element, is resilient and elastic.
As is the case with all inward-opening fuel injection valves, the direction of flow of the fuel at the valve seat is the same as the closing movement of the valve closing element, i.e., the valve needle. When the valve is in the closed position, the fuel is present on the upstream side of the valve seat at a pressure that acts in the valve's closing direction so that when the valve opens the fuel acts against the valve needle's opening direction.